To provide a method for producing grape juice and grape-derived materials enriched with the content of resveratrol.

The grape juice is produced by adding at least any one of ascorbic acid (salt) and erythorbic acid (salt) to squeezed grape juice during or directly after the squeezing by 100-10,000 mg per 1 L squeezed liquid and further heat-treating. Also, the fruit grain or fruit juice is produced by immersing the grape fruit grains in any one of an aqueous ascorbic acid (salt) solution and an aqueous erythorbic acid (salt) solution, and further heating.